Lift-cutting maul.



D. PARKS.

LIFT CUTTING MAUI.. APPLICATION man JAN. 7. Isls.

Patented .Tune 5, 1917.

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DENNIS PARKS, F ST. LOUIS, MISSOURI.

LIFT-CUTTING MAUL.

Specification of Letters Patent.

Patented June 5, 1917.

Application filed January t', 1916. Serial No. 70,749.

i into a die in matched relation to form pieced lifts, and has for its general object to enable such operations to be performed with facility and rapidity, and with the exercise of the minimum of muscular exertion by the operator.

As practised prior to my invention, a relatively heavy maul was used for straightedging the leather, and for cutting it into the die, and this maul was raised by one hand of the operator and brought down with some degree of force on the piece of leather held by his other yhand over the straightedging blade, and then over the die, and

- these operations were repeated by a .single operator perhaps several thousand times in the course of'a days work. Such operations were necessarily very fatiguing, and only an operator possessing more than the average strength and endurance could perform such work continuously during the entire day, the average operator finding it necessary to rest his arm at more or less frequent intervals. As compensation for this character of work is usually based on the number of lifts cut during the course of the day, the pay of the operator was curtailed by reason of such periods of inaction, and the output of the factory in this regard proportionately reduced.

According to my invention I mount a maul, much heavier than that ordinarily employed for the operations indicated, Von the lower end of a relatively long coil spring which is suspended from a suitable support above the head of the operator. The weight of the maul and the strength of the spring are so proportioned to each other that the weight of the maul will be overcome by the tension of the spring when the bottom of the maul is slightly below the top of the die or straight-edging blade. In practicel provide that the maul shall be in balanced relation when it is at rest on the table on which the die and straight-edge arel mounted. This manner of mounting the maul, as will be apparent, will permit the operator to raise it with the expenditure of scarcely an appreciable amount of power, and will also permit of his bringing the maul down upon the die or straighteedge with the requisite degrec of force with the exercise of the like minimum amount of power, the inertia of the maul, when started on Yits downward course, owing to its considerable weight, being nearly sufcient to complete the stroke with the proper degree of force without the expenditure of power by the operator.

As shown by the accompanying drawing, it is the practice to place the straight-edging blade immediately behind the die, and even with a spring-balanced maul with the s drin@r attached to the top of the maul, the operation would involve. considerable strain on the wrist of the operator in moving the maul to a position over the straight-edging blade and in overcoming the tension of the spring to bring the bottom of the maul to a position parallel with the top of the blade. To overcome this objection I secure the lower end of the supporting spring toward the lower end of the maul, or at what may be termed its center of gravity, and weight the upper end of the maul'A above the handle, or part grasped by the operator, so that the maul may be overbalanced with the expenditure of but slight power.

The invention is illustrated in the accompanying drawing, in which- Figure l is a view partly in side elevation and partly in section showing a maul mounted for operation according to my invention, in connection with a straight edging blade and a die secured in position on a table;

Fig. Q.' is a vertical sectional view of the maul and showing in elevation the lower portion of the spring supporting the same; and

Fig. 3 is a bottom plan view of the handle portion of the maul.

Referring now to the drawing, the numeral l indicates a table upon which is mounted a straight-edging blade 2, and a die 3 in the usual manner. Mounted on the top of this table and toward the rear side thereof is a standard t which is provided with a fianged base 5 by means of which it may be secured to the table by suitable bolts or screws 6. The upper portion of the standard 4 is curved inwardly, or toward the operator, as indicated at 7, and its outer end is apertured at 8 to support a suitable vgenerally by the numeral 11. This maulA comprises a handle portion 12, an enlarged bottom portion 13 which is provided on its under side with a socket 14,`and an upper weighted portion 15, the parts described presenting in their entirety somewhat the shape of an ordinary dumb-bell. The upper wall of the socket 14 is provided with a transverse groove 16, anda conical opening 17 extends through the part of the maul described from its upper end into the socket 14, the opening 17 tapering inwardly from its upper to its lo-wer end. The lower portion of spring 10 is attached to the maul by a joint which permits the maul to move relatively to the cable or spring. For this purpose the lower end portion of the spring 10 passes through this opening 17, and at its lower end is secured centrally of a rod 18 which is seated in the groove 16. A circular `wooden block 19 is secured in the socket 14 in the usual manner, and serves to prevent the rod 18 from leaving the groove 16. The upper portion of the maul, that is, the handle 'portion 12, bottom portion 13, and upper weighted portion 15, is preferably cast as an integral structure from iron, and, when the block 19 is secured in position in the socket 14, the maul as a whole is of considerably greater' weight than that usually employed in the ordinary hand operation.

Evidently each time the maul is raised to strike, the spring assists the musculareffort of the person operating the maul. The weight of the maul is suflicient to overcome f the force of the spring and normally hold the maul in a depressed position.

The tapered opening permits of the distortion of the spring 10 in moving the maul from the die 3 to a position over the straight-edging blade 2, as shown by dotted from a position over the die toa position over the straight-edging blade, which necessarily involves the exertion of some force to distort the spring 10; and moreover that such distortion of the spring is minimized by providing the tapering opening 17, which will permit a wide latitude of movement of the maul from a position over the die without bringing the spring into contact with the walls of said opening.

The spring is of such strength that the weight of the maul will extend it sufficiently to hold the maul substantially. at the level at which the maul is reciprocated, that is to say, the handle 12 of the maul is normally held within the zone of movement of the maul when in operation.

The manner of using the maul in straightedging leather and cutting the lifts` into the die has been referred to generally above, and such general operation being well known a further description thereof would seem to be unnecessary.

I cla-im:

1. A device of the character described comprising a maul having, a substantially vertically elongated handle for raising the maul and striking downwardly in a substantially vertical plane, and a spring -pulled pendent supporting member attached to said maul substantially at the center of gravity thereof.

2. A device of the character described comprising a maul and a pendent spring connected at its lower end to said maul at approximately the center of gravity thereof.

3. A device of the characterA described comprising a maul provided with a downwardly-tapering opening, and a pendent spring extending into said opening and connected at its lower end to said maul at approximately the center of gravity thereof.

4. A device of the character described comprising a maul having a handle-portion and being weighted above and below said handle portion, and a pendent spring con-V nected at its lower end to said maul at approximately the center of gravity thereof.

5. A .device of the character described comprising ya maul having a tubular handle, and resilient means including a cable suspended from above, and freely movable laterally below, the lower portion of said cable passing into said tubular handle and having a joint connection withfsaid maul permitting a movement of said maul with respect tosaid cable about said joint. 4

In testimony whereof, l have hereunto set my hand.

DENNIS ranks.

Copies of this patent may be obtained for ve cents each, by laddressing the Commissioner of Patents.

' Washington, D. C. 

